546 THE POPULAR SCIENCE MONTHLY. 



a race if left to multiply. Here, again, in the case of animals, the dif- 

 ference from race to race is much greater than in the case of man. 



Sometimes, in the presence of variations of color like these we have 

 described, we ask if, between the negro and the white, there do not 

 exist anatomical differences in the skin? The minute study of this 

 organ answers us in the negative. 



The skin is composed of three layers, which together constitute a 

 true organ having its proper functions. So it is often called the cu- 

 taneous organ. On the exterior is the epidermis, that dry and in- 

 sensible layer which covers the entire body, and protects it against the 

 action of outer agents. 



Interiorly, and immediately above the greasy body, is the true 

 skin it is the essential and living part of the cutaneous organ ; it is 

 this which receives the blood-vessels and nerves. 



Between the true skin and the epidermis is a dark layer, composed 

 of distinct cells. It is the mucous membrane of Malpighi, so named 

 from the anatomist who first described it. The cells that form it are 

 a simple secretion of the true skin. It is this layer which is the seat 

 of color. It exists in all men, but the cells that it contains are more 

 or less colored according to race. In whites themselves, in certain 

 parts of the body, around the nipples, in the specks of freckles, in the 

 beauty-spots, etc., we sometimes see them as deep as in the negro. 



You see that the color in different human races is, when developed, 

 only a phenomenon of local coloration, of exactly the same nature as 

 those we encounter in races of domestic animals. If time permitted 

 me to enter more fully into the subject, I could make this fact much 

 more evident, but the hour advances and I must hasten. 



To the skin are attached a certain number of organs, which may be 

 considered as adjuncts to the cutaneous organ. These are chiefly the 

 villosities or hairs, the sebaceous glands, and the sweat-glands. Be- 

 tween these annexed organs there exists a certain balance which 

 physiology easily explains. So in glabrous races, that is, races with 

 little or no villosities on the body, the sebaceous apparatus is much 

 more developed. This fact is very marked in the African negro, whose 

 skin sometimes bears slight prominences, sketching a sort of arabesque 

 by the extraordinary development of these little organs. 



It is to the development of the sebaceous apparatus that the odor 

 developed by the negro is due. This odor is so strong, so persistent, 

 that it suffices to the identification of a negro-ship a long time after it 

 has left the trade. But it is not negroes alone that are characterized 

 by malodorous exhalations. It is the same with the whites themselves. 

 You all know that a dog follows his master by the scent. Savage 

 people, whose senses are more exercised than ours, distinguish very 

 quickly the general odor which characterizes a race ; and, in Peru, they 

 give special names to that of the white and of the black as well as to 

 their own, 



